why do mountain bikes use presta valves

Why Do Mountain Bikes Use Presta Valves

why do mountain bikes use presta valves

Newer mountain bikes have Presta valves, but it wasn’t always like this. Everything else which has a tire that needs air uses Schrader including mountain bikes. So why the switch.

Why do mountain bikes use Presta valves? Mountain bikes have Presta valves because they are thinner, lighter, longer, and easier to inflate. These valves are more accurate when deflating, they handle high pressure better, they are equipped with a lockring, the valve does not sink in, and it does not get clogged up.

Let’s see how these reasons help you when you are using Presta valves.

How Do Mountain Bikers Use Presta Valves

  • Mountain bike wheels which are thinner have thinner rims and therefore have a smaller hole in the rim for the valve. Presta valves are made thinner in order to fit these thinner rims. Also, because the rim has a smaller hole for the valve this makes the rim stronger overall.
  • Some riders are real weight weenies on the trails. They want to have their bike as light as possible. Presta valves are lighter than Schradar valves. The difference is not very much 1 gram or 2, but some riders feel mentally more confident when they know their bike is as light as they can make it.
  • Cross country riders like to go as fast as possible so they take any advantage they can. Some use deep section wheels or aero rims. These rims are thicker so they have a longer valve. Presta valves are made longer for this type of wheel.
  • Presta valves are easier to inflate because the valve head closes immediately after you stop inflating. Air does not escape out when you remove the nozzle of the inflator. This helps to inflate the tire more accurately.
  • This is especially useful when you are using a floor pump because there is a pause between pumps. The valve head closes every time you release the pressure. You will not lose any air when you release the pressure in order to re-pump the floor pump.
  • Depending on where you are riding you might want more traction. An easy way to get more traction is to deflate your tires a little bit. But you don’t want to deflate them too much otherwise you will need to re-inflate them.
  • Presta valves allows you to deflate your tire a little bit at a time. All you need to do is tap your finger on the valve head quickly and a little bit of air will escape. It has not been proven, but it has been said that each time you tap the Presta valve 2 psi of air is released.
  • Many riders pump their tires using a hand pump. Presta valves are more durable in this situation because the valve can move from side to side inside the hole. This can damage the tube. Presta valves have lockrings you can use to prevent movement and stress at the point where the valve and tube meet.
  • Presta valves are good at handling high pressure tires. This is because it is the air pressure from the tire which keeps the valve closed. This is ideal for mountain bikers because these riders go on rough terrain which puts a lot of pressure on the tires. You don’t want to lose air through the valve because of high pressure from the trails impact on the wheels.
  • Trail riders go through dirty and muddy terrain. This can cause your wheels to get pretty dirty and muddy. This can cause your tire valve to get clogged up with dirt and mud. But with a Presta valve this does not happen when you spin the valve closed. You don’t need a valve stem cap, which is convenient because they can get lost.

How To Inflate a Mountain Bike Tire Using a Presta Valve

  1. First rotate the tire so the Presta valve is at its lowest point near the floor.
  2. Remove the valve stem cap if one is on there.
  3. Unscrew the nut counterclockwise to open the valve. Unscrew it until it gets to the end of the thread, but do not remove it.
  4. Tap the end of the valve with your pointer finger two times. This will clean out any dirt and confirm that the valve is working correctly.
  5. Place the pump head on to the Presta valve and lift the lever of the pump to lock it in to place to the Presta valve.
  6. Begin inflating the tire to the pressure you want.
  7. Flip the lever of the pump back to its beginning position to unlock the pump from the Presta valve.
  8. Carefully remove the pump head from the valve.
  9. Turn the nut clockwise to close the valve.
  10. Put the valve stem cap back on for protection.

Do Presta Valves Come in Different Sizes

The most common Presta valve size is 32mm. There are larger sizes such as 48mm and 60mm. Most mountain bikes will just need to use a 32mm Prests valve. These valves are threaded and may or may not come with a dust cap. All of them come with a nut towards the top and a lock ring.

What is the Cost of a Replacement Presta Valve

If you want to replace the entire Presta valve then you need to buy another tube for the tire. If you do not want to do that then you need to replace the Presta valve core. The Presta valve core is inside the Presta valve.

You can buy 10 Presta valve cores by Kenda on amazon for 10.99. So basically just over a dollar per valve core. Vittoria sells a pack of 10 for 14.99 on amazon as well. You can buy a pack of 4 valve cores on ebay for 1.50. It might be better to go with a brand name for higher quality.

How To Put Slime Into a Presta Valve

  • The most common way to put slime into a Presta valve is to remove the top nut on the Presta valve using a wrench. Once it is loose enough then you can screw it off with your pointer finger and thumb.
  • The next way you can add slim is to remove the valve core from the Presta valve. For this you will need a valve core remover tool. These are inexpensive and easy to get. Place the valve core remover into the valve. Push it so it goes all the way in, then twist and unscrew the valve core and pull it out.
  • If you want to bypass the Presta valve you can use a flavor injector to inject the slim into the inner tube. Using the needle of the injector push through the inner tube carefully near the valve. Then just push down on the plunger so the slim is pushed out of the barrel into the needle and into the inner tube.

What is a Presta Valve Adaptor Good For

A Presta valve adapter allows you to pump up and inflate your tire using a pump which is not compatible with a Presta valve. Many pumps, compressors, and and all gas station will not fit on to a Presta valve.

So just buy a Presta valve adaptor. Then unscrew the nut on the valve until it reaches the end of the thread. Then screw on the adaptor on to the Presta valve. Now you can inflate your tire using other types of pumps by connecting it to the adaptor.

How Are Presta Valves Different From Schrader Valves

Presta valves are tall while Schrader valves are short in height. Presta has a thin valve while the Schrader valve is thicker. Presta valves use a valve core inside as a means to send air into the tube. A Schrader valve has a cylinder in the valve and under the cylinder is a spring.

Presta valves have a nut which opens and closes the valve when you screw or unscrew it. A Schrader valve does not. Presta valve inner tubes are deflated by unscrewing the nut to the end of the thread. Then push down with your finger the tip of the valve. Schrader valves release air when you push down on the cylinder inside the valve.